Roughing is the first lathing, done after roto-casting. During the roto-cast, the fluid bronze is poured in the mold which rotates at some hundred rounds per minute. Any impurities in the bronze alloy are thus carried to the outer zone of the cymbal. This outer shell is afterwards removed by a machine controlled lathe with a coarse tool tip. Plenty of bronze is removed during the process, since not only the dull-grayish cast surface is cut off, but the cymbal is at the same time reduced to its final thickness. The unlathed interior of the cup still shows the rock-like color with rings coming from temperature differences at tempering.